EP0414678B1 - Höhenregelungssystem für ein fahrzeug mit luftfederung - Google Patents

Höhenregelungssystem für ein fahrzeug mit luftfederung Download PDF

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Publication number
EP0414678B1
EP0414678B1 EP19880903239 EP88903239A EP0414678B1 EP 0414678 B1 EP0414678 B1 EP 0414678B1 EP 19880903239 EP19880903239 EP 19880903239 EP 88903239 A EP88903239 A EP 88903239A EP 0414678 B1 EP0414678 B1 EP 0414678B1
Authority
EP
European Patent Office
Prior art keywords
height
adjustment system
height adjustment
characteristic curve
vehicle body
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP19880903239
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English (en)
French (fr)
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EP0414678A1 (de
Inventor
Jürgen PISCHKE
Engelbert Tillhon
Matthias Fahrnschon
Helmut Zehaczek
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP0414678A1 publication Critical patent/EP0414678A1/de
Application granted granted Critical
Publication of EP0414678B1 publication Critical patent/EP0414678B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
    • B60G17/015—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements
    • B60G17/0152—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements characterised by the action on a particular type of suspension unit
    • B60G17/0155—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements characterised by the action on a particular type of suspension unit pneumatic unit
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S280/00—Land vehicles
    • Y10S280/01—Load responsive, leveling of vehicle

Definitions

  • the present invention relates to a height adjustment system of the kind described in the pre-characterising clause of claim 1.
  • a height adjustment system of the kind described in the pre-characterising clause of claim 1.
  • Such a system is known from EP-A-0091017 wherein compressed air is admitted to the air spring when a distance sensor senses that the height of the vehicle body is below a lower threshold and air is released from the air spring when the distance sensor senses that the body height is above an upper threshold.
  • the adjustment travel extends beyond that at closure of the solenoid valve arrangement.
  • An attempt to compensate for this overshoot is made by appropriate choice of the upper and lower thresholds. However, this does not take into account the fact that the amount of overshoot depends also on the velocity of vertical movement of the vehicle body relative to the axle at the instant of closure of the valve arrangement and possibly other factors.
  • the invention is readily realized by the use of a characteristic curve stored in a memory in accordance with claim 2. Sufficient accuracy can be obtained by adopting the measures of claims 3 and 4.
  • the characteristic curve can be determined empirically or by trial and error in accordance with claim 5 or 6.
  • the stored characteristic can be corrected or a choice out of a range of stored characteristics can be made, in accordance with claim 7. This has the advantage that compensation can be made for changes which occur in the friction and damping characteristics while the vehicle is in use.
  • Fig. 1 shows diagrammatically a part of a vehicle body 10 attached to an axle 12 by an air suspension 14.
  • the air suspension 14 comprises an air spring bellows 16, an oscillation damper 18 and a height measuring sensor 20, each arranged between the vehicle body 10 and the axle 12.
  • the height measuring sensor 20 can be a simple potentiometer or variable resistor.
  • the air spring bellows 16 is filled and emptied as required by a compressed air reservoir 22 and a solenoid valve arrangement 24.
  • the reservoir 22 is charged from a compressor (not shown) via a line 26 containing a non-return valve 28.
  • the valve arrangement 24 comprises a 3-port, 2-position valve 30 and a 2-port, 2-position valve 32 in a line 34 between the reservoir 22 and the suspension bellows 16.
  • valves are spring-biased to their positions shown and are operated by solenoids 36, 38 with the assistance of air pressure from the reservoir 22.
  • solenoids 36, 38 With the assistance of air pressure from the reservoir 22.
  • the valve arrangement 24 cannot be opened.
  • Actuation of both valves 30, 32 connects the air spring bellows 16 to the reservoir 22 in order to feed compressed air to the air suspension 14 and thereby increase the height h of the vehicle body 10 relative to the axle 12.
  • Actuation of the valve 32 alone connects the air spring bellows 16 via the unactuated valve 30 to exhaust and thereby decrease the height h of the vehicle body 10.
  • the height sensor 20 is connected to a comparator 40 for raising the vehicle body and to a comparator 42 for lowering the body.
  • the outputs of the comparators 40, 42 are connected to a control computer 44 which energises the valve solenoids 36, 38 via end stage amplifiers 46, 48; respectively.
  • the output h of the height sensor 20 is differentiated in a differentiator 50 to obtain the velocity ⁇ of vertical movement of the vehicle body and this velocity ⁇ is fed to a memory zone 52 (which may be part of the computer 44) in which is stored a characteristic curve.
  • This characteristic curve which is shown in Fig. 3, gives the amount ⁇ by which the switching thresholds for the comparators 40 and 42 must be adjusted to compensate for the frictional forces in the oscillation damper 18.
  • the required threshold adjustment ⁇ is directly proportional to the velocity of vertical movement of the vehicle body so that the majority of the characteristic curve is represented by a straight line of suitable slope.
  • ⁇ min at velocities below V min which is determined by the expected errors of measurement and calculation.
  • ⁇ max at velocities above V max which is determined by the air pressure in the reservoir 22, the capacity of the air spring bellows 16 and the flow cross sections of the valves 30, 32 and the air line 34.
  • a subtractor 54 the height adjustment ⁇ is subtracted from a height value h 1 which it is desired to obtain when increasing the body height h from a too low a value.
  • the height adjustment ⁇ is added to a height value h 2 which it is desired to obtain when the body height h is decreasing from a too high a value.
  • the outputs of the subtractor 54 and the adder 56 are applied to the reference inputs of the comparators 40 and 42, respectively.
  • h 1 should equal h 2 but, in practice, it is necessary to build some hysteresis into the system to avoid an excessive number of readjustment operations. Nevertheless, it is possible to feed the same desired height value h o to both the subtractor 54 and the adder 56 if the minimum threshold adjustment ⁇ min is increased to establish the hysteresis.
  • the comparator 40 supplies a signal to the computer 44 which energises both valve solenoids 36, 38, whereby to admit compressed air to the air spring bellows 16.
  • the velocity ⁇ of the consequent height adjustment is fed to the memory zone 52 which delivers a threshold adjustment ⁇ determined by the stored characteristic curve.
  • the switching off threshold of the comparator 44 is thus adjusted to h 1- ⁇ , whereby the computer 44 closes the valves 30, 32 before the desired body height h 1 (or h o ) is reached.
  • the stored characteristic curve is so chosen that the body reaches the desired height h 1 (or h o ) when the frictional forces in the damper 18 have dissipated.
  • the comparator 42 signals the comparator 44 to energise only the solenoid 38 of the valve 32, whereby to discharge air from the air spring bellows 16.
  • the valve 32 is closed when the height h reaches the switching off threshold h 2 + ⁇ to establish the desired body height h 2 (or h o ) when the frictional forces have dissipated.
  • V min 5 mm / sec
  • V max 50 mm / sec.
  • the height adjustment falls short of the desired value in the case of low adjustment velocities and overshoots the desired value in the event of high adjustment velocities.
  • the actual adjustment may depart by ⁇ 15 mm from the desired value.
  • this departure can be reduced to ⁇ 2 mm when the vehicle is stationary. Due to vehicle oscillations when the vehicle is moving, the deviation from the desired value is increased both with and without the invention, in spite of filtering of the measured height signals from the sensor.
  • the characteristic curve of Fig. 3 can be established empirically by making measurements of the actual adjustment velocity ⁇ and the consequent value of the eventual overshoot when the frictional forces have been overcome or dissipated. Another way is by trial and error. An initial characteristic curve is established arbitrarily and the error in the eventual height adjustment actually produced by the system is noted. The characteristic curve stored in the memory zone is then changed in a sense to reduce this error. The process is then repeated as often as is necessary to bring this error down to an acceptable value. In the trial and error method, the corrected characteristic curve can be stored in a non-volatile memory, to avoid having to correct a fixed characteristic curve each time the system is switched on. There is also the possibility of obtaining suitably accurate characteristic curves for individual systems, e.g., to compensate for differences in flow cross sections of valves and conduits and aging of the damper.
  • the invention avoids the need for a compromise which would result from an adjustment to give optimum height regulation at half load and the consequent poorer regulation at smaller and larger loads.
  • the comparator 44 is programmed to adjust the characteristic curve stored in the memory zone 52.
  • the measured height h is compared with the desired value h o in a further comparator 60 and the error is fed to the computer 44. If this error is over a predetermined value in the steady state, i.e. in the absence of any signals from either of the comparators 40, 42, a corresponding correcting signal is fed to the memory zone 52 to alter the characteristic curve in the sense that the error will be reduced the next time an adjusting operation takes place.
  • two oppositely poled comparators 60 would be needed for making corrections in either direction as may be necessary. If a volatile memory 52 is used, the one characteristic curve can be corrected as necessary.
  • An alternative would be to use a non-volatile memory in which a series of characteristic curves is stored, of which only one is used at any given time. In such case, the correcting signal from the computer 44 changes the characteristic curve in use.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Vehicle Body Suspensions (AREA)

Claims (7)

1. Niveauregelungssystem für ein Fahrzeug mit Luftfederung und einem Dämpfer (18), mit einer Anordnung (24) von Magnetventilen zur Zuführung von Druckluft zu den Luftfedern (16) und zum Ablassen von Luft aus den Luftfedern (16), einer Meßeinheit (20) zur Messung des Abstandes zwischen Achse und Fahrzeugaufbau und einer Regelungseinheit (44) zur Ansteuerung der Ventilanordnung (24) abhängig von dem von der Meßeinheit gemessenen Abstand, um diesen Abstand mehr oder weniger unabhängig von der Fahrzeugbeladung unverändert zu halten, dadurch gekennzeichnet, daß der Zeitpunkt oder die höhe (h), bei dem oder bei der die Regelungseinheit (44) die Magnetventilanordnung (24) schließt, abhängig von der Geschwindigkeit (V) der vertikalen Bewegung des Fahrzeugaufbaus (10) relativ zur Achse (12) ist.
2. Niveauregelungssystem nach Anspruch 1, wobei die Regelungseinheit (44) die Magnetventilanordnung bei einer gewünschten Höhe (h) des Fahrzeugaufbaus schließt und die gewünschte Höhe durch eine Schwelle (α) gegeben ist, die durch die Geschwindigkeit (V) der vertikalen Bewegung in Übereinstimmung mit einer Kennlinie, die im Speicher (52) gespeichert ist, bestimmt wird.
3. Niveauregelungssystem nach Anspruch 2, wobei die Schwelle (α) wenigstens in einem Teil der gespeicherten Kennlinie proportional zu der Geschwindigkeit (V) der vertikalen Bewegung des Fahrzeugaufbaus (10) ist.
4. Niveauregelungssystem nach Anspruch 2 oder 3, wobei die gespeicherte Kennlinie von einer Minimalschwelle αmin, bei der die Geschwindigkeit (Vmin) innerhalb der Meßungenauigkeit ist, bis zu einer Maximalschwelle αmax reicht, bei der die Geschwindigkeit (Vmax) in Anbetracht der verfügbaren Druckluftversorgung maximal wird.
5. Niveauregelungssystem nach Anspruch 2, 3 oder 4, wobei die gespeicherte Kennlinie empirisch bestimmt wird.
6. Niveauregelungssystem nach Anspruch 2, 3 oder 4, wobei die gespeicherte Kennlinie durch die Vorgehensweise "Versuch und Irrtum" bestimmt wird.
7. Niveauregelungssystem nach Anspruch 2, 3 oder 4, wobei nach einer Verstelloperation die momentane Höhe (h) des Fahrzeugaufbaus mit der gewünschten Höhe (h₀) verglichen wird und dann, wenn als Ergebnis ein Fehler (h-h₀) einen vorbestimmten Wert übersteigt, die vorliegende Kennlinie im Sinne einer Fehlerreduzierung gewechselt oder geändert wird.
EP19880903239 1988-04-08 1988-04-08 Höhenregelungssystem für ein fahrzeug mit luftfederung Expired - Lifetime EP0414678B1 (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP1988/000295 WO1989009701A1 (en) 1988-04-08 1988-04-08 Height adjustment system for a vehicle with air suspension

Publications (2)

Publication Number Publication Date
EP0414678A1 EP0414678A1 (de) 1991-03-06
EP0414678B1 true EP0414678B1 (de) 1992-01-15

Family

ID=8165259

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19880903239 Expired - Lifetime EP0414678B1 (de) 1988-04-08 1988-04-08 Höhenregelungssystem für ein fahrzeug mit luftfederung

Country Status (5)

Country Link
US (1) US4971360A (de)
EP (1) EP0414678B1 (de)
JP (1) JP2695216B2 (de)
DE (1) DE3867850D1 (de)
WO (1) WO1989009701A1 (de)

Families Citing this family (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5367459A (en) * 1992-02-10 1994-11-22 Trw Inc. Apparatus for controlling dampers in a vehicle suspension system
US5430647A (en) * 1992-12-07 1995-07-04 Ford Motor Company Method and apparatus for maintaining vehicular ride height
DE4333823A1 (de) * 1993-10-04 1995-04-06 Bosch Gmbh Robert Vorrichtung zur Niveauregelung eines Fahrzeugs mit Luftfederung
US5517847A (en) * 1994-12-16 1996-05-21 Ford Motor Company Open compartment load leveling ride height control
DE19853126B4 (de) * 1998-11-18 2005-03-03 Daimlerchrysler Ag Verfahren zur Niveauregelung und Radfahrzeug mit einem Niveauregelsystem
KR100475906B1 (ko) 2001-10-19 2005-03-10 현대자동차주식회사 에어서스펜션 차량의 롤 스태빌라이저 장치
US8306696B2 (en) * 2003-04-17 2012-11-06 Driveright Holdings, Ltd. Method and system for aligning a vehicle with an artificial horizon
ES2335016T3 (es) * 2003-04-17 2010-03-18 Firestone Industrial Products Company, Llc Procedimiento y sistema de alineacion de un vehiculo estacionario con un horizonte artificial.
US7192012B2 (en) * 2003-08-18 2007-03-20 Haldex Brake Corporation Air suspension system with supply air restriction valve
US6935625B2 (en) * 2003-08-18 2005-08-30 Haldex Brake Corporation Air suspension system with air shut off valve
DE102004021726A1 (de) 2004-04-30 2005-11-24 Daimlerchrysler Ag Verfahren zur Niveaueinstellung eines Fahrzeugs
US7744099B2 (en) * 2004-11-04 2010-06-29 Driveright Holdings, Ltd. Method and system for adjusting a vehicle aligned with an artificial horizon
KR100784377B1 (ko) * 2005-12-07 2007-12-11 주식회사 만도 선형 차고 센서를 구비한 차량의 현가장치 및 차고 제어방법
US8155835B2 (en) * 2008-02-21 2012-04-10 Driveright Holdings, Ltd. Vehicle chassis height adjustment method and system
US8191904B2 (en) * 2009-10-02 2012-06-05 Barksdale, Inc. Hybrid leveling system
DE102009057529A1 (de) * 2009-12-08 2011-06-09 Iav Gmbh Ingenieurgesellschaft Auto Und Verkehr Verfahren zur Steuerung der Niveauregulierung eines Fahrzeugaufbaus eines Kraftfahrzeuges
US8868294B2 (en) 2012-09-28 2014-10-21 Firestone Industrial Products Company, Llc Adjustable hysteresis circuit for control of air suspension
US10479159B2 (en) 2016-04-04 2019-11-19 Barksdale, Inc. Ride height leveling with selectable configurations: system and method

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0262572A2 (de) * 1986-09-27 1988-04-06 Bayerische Motoren Werke Aktiengesellschaft, Patentabteilung AJ-3 Verfahren zur Dämpferkraftverstellung von Kraftfahrzeugen

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JPS58174007A (ja) * 1982-04-06 1983-10-13 Nissan Motor Co Ltd 自動車高調整装置
JPS59191803A (ja) * 1984-04-02 1984-10-31 株式会社荏原製作所 水管ボイラ
JPS61163011A (ja) * 1985-01-14 1986-07-23 Nissan Motor Co Ltd 電子制御ショックアブソ−バ装置
JPH0710643B2 (ja) * 1985-10-22 1995-02-08 トヨタ自動車株式会社 車輌用車高調整装置
JPS62214008A (ja) * 1986-03-13 1987-09-19 Komatsu Ltd ホイ−ル式クレ−ンのサスペンシヨン制御装置
JPS63284011A (ja) * 1987-05-13 1988-11-21 Fuji Heavy Ind Ltd 自動車用アクティブサスペンションの制御方法

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0262572A2 (de) * 1986-09-27 1988-04-06 Bayerische Motoren Werke Aktiengesellschaft, Patentabteilung AJ-3 Verfahren zur Dämpferkraftverstellung von Kraftfahrzeugen

Also Published As

Publication number Publication date
JPH03503621A (ja) 1991-08-15
WO1989009701A1 (en) 1989-10-19
DE3867850D1 (de) 1992-02-27
EP0414678A1 (de) 1991-03-06
JP2695216B2 (ja) 1997-12-24
US4971360A (en) 1990-11-20

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